Performance and carcass yields of Ile de France lambs weaned at different ages

Abstract

The objective of this study was to evaluate the performance, biometrics measures, yields and carcass commercial cuts and non carcass components from lambs weaned at 45 or 60 days of age and slaughtered at 32kg body weight. Sixteen male lambs, confined individually after weaning to reach slaughter body weight were used. The lambs were slaughtered and their carcasses were weighed to determine hot carcass and true yields. The non carcass components were weighed separately and then calculated their percentages in relation to slaughter body weight. After 24 hours of cooling, the cold carcass yield and weight loss by cooling were determined. The carcasses were sectioned in five commercials cuts. There was no difference between treatments for birth weight (3.73kg); weight at weaning (14.55kg); daily weight gain (0.283kg/animal/day) and feed conversion (3.13). The lambs weaned at 60 days showed higher dry matter intake (0.908kg/animal/day), lower time of confinement (56 days) and age at slaughter (116 days). The gastrointestinal tract and its contents represented the highest percentage in relation to slaughter body weight (17.25%). There was difference only for losses to fasting, with values of 4.47 and 6.87% for animals weaned at 45 and 60 days, respectively. The ages at weaning did not alter the performance, yields and the quantitative carcass characteristics of lambs slaughtered at 32kg body weight, however, lambs weaned at 60 days demanded less time to reach slaughter weight may be more economically viable for the farmers.